The Eola-Amity Hills AVA, stretching from the town of Amity in the north to Salem in the south, is hard to miss visually. It's a self-standing geological feature in the middle of the Willamette Valley -- a curving chain of hills that is the product of an ancient collision between the Pacific and North American plates.

All of the grape-bearing soils in the 37,900-acre AVA are volcanic in origin. They range in type from nekia, which tends to be somewhat shallow, to jory, which is 6 to 7 feet deep.

Apart from the soils, this AVA's most distinctive feature may be the Van Duzer breezes that produce the greatest range of daytime temperatures of any AVA in western Oregon.

The breezes are named for the Van Duzer Corridor, a low point in Oregon's Coast Range. The steady, predictable breezes pour in from the ocean, bringing down afternoon temperatures as they fan across the valley. As they enter the valley, they flow directly toward the Eola-Amity Hills.

The name Eola, in fact, was adapted from Aeolus, who was a minor deity of the ancient Greeks in charge of the winds.

"We get as warm as any place in the valley in the middle of the day," says Ted Casteel, a co-founder of Bethel Heights Vineyard in Salem. "But by late afternoon, the Van Duzer winds come in, bringing cool marine air with them."

The result, he said, is wine with great complexity, balance and finesse.

"Our wines are described as more red-fruited than black-fruited," Casteel said. "They are considered to be a little brighter than some others, which means they have more acidity."

Relatively few wineries are within the AVA, partly because it is farther from population centers. That lack of wineries, however, is more than made up for by the prestigious vineyards there.

Wineries not headquartered in the AVA, but who maintain vineyards there, include Ken Wright Cellars, Domaine Serene and Argyle Winery.

Most vineyards are planted in the center of the hills or on the eastern slopes.

In order for a winery to use the Eola-Amity Hills AVA on its label, most of the grapes that went into the wine must have been grown inside the AVA.

"The really great thing about having it on the label is that it allows us to tell our story to every new customer who comes into the tasting rooms here," Casteel says. "As with the other relatively new AVAs in Oregon, the names are becoming invested with more and more meaning as time goes by."